Inertia responsive magneto generator



United States Patenti() The present invention relates to magneto generators and more particularly to a new and improved inertia responsive magneto generator particularly well suited for use with ordnance devices operable upon impact or sudden changes in acceleration or deceleration.

Inertia responsive magneto generators heretofore devised generally have taken the form of an initially closed magnetic circuit for a voltage generating coil in which the magnetic circuit includes an inertia responsive element and a permanent magnet which in some cases is also employed as the inertia responsive element.

In certain of the prior art generators such, for example,

as that disclosed'in the patent to Edmund L.V Zalinski for I Magneto-Electric Fuse, No. 384,662, the generating coil is arranged to link all of the flux lines of the Ainitially closed magnetic circuit such that upon movement of the inertia responsive element out of the magnetic circuit,4 the fluir linkages of the coil with the magnetic circuit are suddenly decreased whereupon a voltage is induced in the coil.

Applicant has found that the output of the voltage generating coil may be greatly increased by arranging the inertia responsive element initially in a closed magnetic circuit unlinked with the coil so that the llux linkages with the coil are suddenly greatly increased from substantially zero as the inertia element moves to open the circuit, the flux lines being transferred to a second magnetic circuit including an air path traversing the coil as the element moves.

An object of the present invention is to provide a new and improved inertia responsive magneto generator. for firing ordnance devices.

Another object is to provide an inertia responsive magneto generator of this character which is se1f-contained and therefore is not dependent for its operation on dry cells, storage batteries or the like, and is compact thereby requiring a minimum of space for installation.

A further object is to provide an inertia responsive magneto generator for the tiring circuit of an ordnance device in which the magnetic flux is transferred from a first path comprising a closed magnetic circuit having no ux linkage with the voltage generating coil to a second path in which the magnetic flux traverses the coil whereby the flux in the path is substantially linked therewith.

A still further object is to provide an inertia responsive magneto generator for the tiring circuit of an ordnance device in which the linkage of the voltage generating coil with the magnetic flux of the magneto generator is effected by the movement of an inertia responsive element out of a closed magnetic circuit for the tiux, thereby producing an induced current output from the coil of sufficient amplitude to operate the tiring circuit.

A still further object is to provide electrical tiring apparatus for ordnance devices which is highly effective for the purpose intended, durable, efficient and simple in op eration, and economical to manufacture.

Other objects and many of the attendant advantages of 70 this invention will be readily appreciated as the same be- 2,820,411 Patented Jan. 21, 1958 comes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. 1 is a sectional view of the nose portion of a bomb and illustrating a fuze including the magneto generator of the present invention;

Fig. 2 is a plan view of the magneto generator pet se;

Fig. 3 is a sectional view taken along line 3-3 of Fig. 2; and

Fig. 4 is a view in diagrammatic form of an electrical tiring circuit for the bomb of Fig. 1 and using the magneto generator of the present invention.

Referring more particularly to the drawings in which like numerals indicate like parts throughout the several views, 10 indicates generally a bomb having a casing 11 and a main charge 12. Secured in the nose of casing 11 is a fuze 13 having contained therein a detonator 14 and a booster charge 15.

A magneto generator indicated generally at 16 is positioned within fuze 13. Magneto generator 16 comprises a cylindrical housing of ferromagnetic material indicated generally at 17. A permanent magnet 18 is centrally disposed within the housing 17 and is secured to the end wall 19 thereof as by a screw 21. The end wall 19 is secured to one end of the cylindrical portion 22 of housing 17 by screws 23. Cylindrical portion 22 has an inturned ange 24 at the opposite end thereof.

Permanent magnet 18 has a flanged spool-shaped core 25 fastened to its end opposite to the wall 19. Core 25 has wound thereon a generator coil 26 having conductors '27 and 28 leading therefrom to the electric detonator 14.

An annular air gap 29 is defined between the liange of cylindrical portion 22 and one of the anges of core 25. An annular armature ring 31 of ferromagnetic material is normally positioned in air gap 29, thereby to complete or substantially close a first magnetic circuit or flux path for permanent magnet 18, the rst tiux path thereof being indicated by dash lines at 32, and to shunt the portion of a second magnetic circuit or ilux path for the magnet indicated by the dashed lines 44. It will be understood that the air gap is no larger than necessary to provide free movement of the ring in the gap thereby to avoid leakage of the flux and resultant linkage thereof with the coil. Secured to armature ring 29 by screws 33 is an annular inertia member 34 of non-magnetic material such, for example, as brass, member 34 being arranged for free movement within housnig 17 in the direction of end wall 19.

The electrical `diagram of Fig. 4 illustrates a simplied arrangement of an electrical tiring circuit for use with the magneto generator of the present invention. The generator coil 26 is connected to one side of detonator 14 by conductor 27. The other end of coil 26 is connected by conductor 28 to wiper contact 35 which normally bears against insulating sleeve 36 of movable switch conductor member 37. On the other side of sleeve 36 a. wiper contact 38 bears thereagainst. Conductor 39 connects contact 38 with the other side of detonator 14. Switch member 37 is threadedly engaged with screw-shaft 41, the shaft being rotated by an impeller 42 as the bomb 10 falls from a launching aircraft. In order to provide a suiiicient time delay before arming the circuit a reduction gear 43 may be interposed between shaft 41 and impeller 42.

In the operation of the device, it is, of course, apparent that the circuit, as illustrated in Fig. 4 is in an open or unarmed condition before the bomb leaves the aircraft. It is also apparent that as the shaft 41 is rotated by impeller 42 as the bomb falls through the air, the movable conductor member 37 moves to its circuit closing position wherein it bridges the gap between contacts 38 and 35 and thereby arms the circuit.

.As .the bomb .Strikes the .Surfae f uthe Water, ,inertia element 34 is suddenly moved forward in response to the set forward force due to the impact, thereby withdrawing'armature 31;fromairgap 2,9. When-.this occurs,

Athe flux in the Amagnetic circuit initially Vclosed lby `the armature, moves to a second pathrbridging ,airgap ,29 in -a predetermined manner effective to traverse coil 26 in 'sufficient quantity to-induce in the coil-:a current suflicient to fire detonator 14 thereby toirefthe-bomb.

A yparticularadvantage of the arrangement of the present inventionresults from the vpositioning-of the coil 26 in such a manner that with the armature 31 in theclosed ,magnetic circuit position, there is substantially no ux linkage' betweenthe coiland the magnetic circuitgiwhereas when the armature is moved kfromtheinitial or closed circuit position, a substantialportionof ;the tluxglines are caused to l follow a new Y path or `circuit r traversing coil .26.

Thus, .the coil produces ra vlarge voltage r output by lreason ofthe ysudden changefrom zero ux Ylinkage to a substantial linkage with the magnetic circuit.

Obviously many modications and variations Lof the present invention are possible-inthe ,light ofrthe-above teachings. lIt is therefore to be understoodvthat .within the scope/of the appendedclaims the inventiommaybe -practiced otherwise than `as specifically described.

vtiring circuit of .an ordnance -device comprising, -infcombination, a ferromagnetic housing of hollow cylindrical formation yone vend thereof being closed the vother end being open and having an inturned flange, a cylindrical permanent magnet axiallyaligned within said housing vand secured at one end tothe closed Vend of `the housing, a flange spool-shaped member of ferromagnetic material mounted on the other end of saidmagnet, an-arma- Ature ring of .ferromagnetic material ynormally lpositioned between one of the anges of the spool-shaped member `and the inturned flange of the housing thereby to close the magentic circuit 4from the magnet throughthehousing, an inertia ring of non-magnetic material .securedto the armature ring andpositioned forzfree movementwithin the housing axially ofthe magnenandan induction coil arrangedin said tiring circuit and wound on thel spool-shaped member whereby a tiring voltage is induced in the tiring circuit as the armature is suddenly moved out of the magnetic circuit upon impact of the ordnance device with its target.

2. An inertia responsive magnet generator comprising, in combination, a cup-shaped ferromagnetic member having an inturned ange on the klip portion thereof, a cylindrical permanent magnetsecured on one end thereofvto the bottom portion of said cup member centrally thereof and terminating Iat .the .otheruend flush with the inner surface ofsaid llange, a `spool-shaped ferromagnetic core member secured tol said other end of the said magnet coaxially therewith `thereby `to detine ,an lannular air gap between said ,flange and the innerange portion of the core member, a coil wound about said core member, an annular ferromagnetic member disposed in said air gap thereby to shunt the magnetic flux of said magnet where- `by substantially Ynoneof said uxfthreads through said vcoil until said annular member is moved out of the air k-gap,vand anon-magnetic inertia responsive member loosely ,sleeved ,about'said-magnet and `secured to said annular member for suddenly withdrawing the annular member from theair lgap yas inertiaforces are appliedtothe magnetogenerator thereby to generate a.voltage in vsaid coil ,proportional tothe rate-of change of flux linkages of the coil-with thefluxof the magnet.

3. Aninertia responsive magnetrgenerator comprising, in combination, a ferromagnetic member, a permanent magnet, means foresecuring said magnet at onefend there- -of tosaid-.ferrornagnetic member, a core member secured toisaidrmagnetat theoppositeend,thereofa coil wound l,onfsaid corefmember, said magnet and said ferromagnetic member Vdefining .an ,air gap, a movable ferromagnetic member initially mountedrin and substantially lling said Aairgap therebyltoshuntthe magnetic flux of said magnet fromsaid coil, andmeansfcr moving said movable member outofsaid airgap ywhereby the iiuxlof said magnet is'causedtoow through .saidcoil thus generating a volt- .age in said coil.

References Citedin the le of this patent :UNITED STATES PATENTS A384,662 Zalinski June 19, 1888 2,404,553 Wales Iuly 23, 1946 FOREIGN PATENTS 506,280 France May 26, 1920 525,333 Great Britain Aug. 27, 1940 

